what size capacitor?
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=78035
Printed Date: April 28, 2024 at 10:33 PM
Topic: what size capacitor?
Posted By: stormraider04
Subject: what size capacitor?
Date Posted: May 19, 2006 at 8:32 PM
i will be getting a system soon and i wanted to know what size capacitor i should get. i will have 1400 watts. my friend says i should get a 20 farad cap. i've heard that you only need 1 farad per 1000 watts. is that true? if going off of that should i only need 2 farad cap? one other question. will a cap keep my system running smoothly or should i upgrade my alternator? either bigger alternator or both bigger alternator and a cap? any help would be great thanks.
Replies:
Posted By: killer sonata
Date Posted: May 19, 2006 at 10:05 PM
If you upgrade you alternator properly you shouldnt even need a cap. If anything you should get a second battery along with the alternator upgrade - one for the stereo and one for the car itself.
Posted By: mobilesndfx
Date Posted: May 20, 2006 at 5:10 AM
You only need a second battery if your going to listen to your system with the car off. Otherwise having multiple batteries wont benefit you. HO alternators can be very expensive, but with 1400 watts, you really need one.
Posted By: jlord16
Date Posted: May 20, 2006 at 7:50 AM
caps do crap all, get a HO alt, best value for money when ur dealing with large power requirments
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Clarion DB36MP
Infinity Kappa Perfect 10"
Respone 800w Mono
ALPINE MRP-F250
*Custom fabrications*
Posted By: stevdart
Date Posted: May 20, 2006 at 8:50 AM
And depending upon what that output rating really means, you may not need an upgraded alt either. Initially, spend your money on upgrading the wiring with extreme detail (see the Big 3 sticky). Install sound damping with equal detail. After the install is complete you will know if an alt upgrade is necessary. And also, if you have an older car with a 3- or 4-year old battery in it, replace the battery right from the start.
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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
Posted By: Aruman
Date Posted: May 20, 2006 at 8:52 AM
do a search on this forum about capacitors, and read this
it will help you understand more about caps. ------------- Shaking The Neighborhood
Posted By: stormraider04
Date Posted: May 20, 2006 at 8:36 PM
if i get a bigger alternator what is a good size to go to?
Posted By: Drewt
Date Posted: May 20, 2006 at 11:44 PM
Basically the biggest one you can afford. Another way - figure out how many amps your alternator puts out now and then add the amps that your amplifier pulls (look for the fuses on the amp if there are any), and add in how many amps you plan to use for an upgrade later, if you can afford it.
Example
Your car puts out 60 amps now
Your amplifier has two 30 amp fuses (60 amps)
You're thinking of adding a 4 channel amplifier in the near future that pulls 40 amps
so:
60+60+40=160
look for a 160 amp alternator, get it if you can, if not, get the largest you can afford.
Posted By: stormraider04
Date Posted: May 21, 2006 at 12:07 AM
is there a certain brand that is better or worse? any good places to get them from?
Posted By: aznboi3644
Date Posted: May 21, 2006 at 1:47 PM
drewt don't forget what the cars electronics already draw. ex. headlights draw about 30 amps. plus the heater and other things. so make sure to add those to the total
Posted By: dragon51
Date Posted: May 22, 2006 at 3:51 AM
This question should really be pined and hi-lighted as often as it come up.
Posted By: stormraider04
Date Posted: May 22, 2006 at 6:10 PM
ok i found out i have a 100amp alternator in my truck right now. adding my 1400 watts in my amplifiers about how big should i go for the alternator? or will i need one?
Posted By: aznboi3644
Date Posted: May 22, 2006 at 6:28 PM
What kind of amp do you have? 1400 watts peak? rms?
Posted By: stormraider04
Date Posted: May 22, 2006 at 7:09 PM
two arc audio amps. the KAR 400.4 and the KAR 1000.V1. the specs say 4x100 watts rms for the 400.4 and 1x1000 watts rms for the 1000.v1. The 400.4 has one 40A fuse the 1000.V1 has three 40A fuses. i dont know if that makes a differnce or not. im not to knowledgeable on this subject.
Posted By: Ravendarat
Date Posted: May 23, 2006 at 1:04 AM
If it was my truck I would be looking in the 160-200 amp range. The max draw on your stereo can in theroy reach 160 but real world use will put it at less than that so once you add in the vehicle itself you should be fine
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double-secret reverse-osmosis speaker-cone-induced high-level interference distortion, Its a killer
Posted By: stormraider04
Date Posted: May 23, 2006 at 7:20 PM
well my mistake i listened to a guy from kragen who told me my stock alternator is 100amps. i called ford today and i actually have a 115 amp alternator. if i dont get a bigger alternator or a cap will i be fine or will i burn something up? the car audio store i was planning on getting all my stuff from said to just get a 5 farad cap. what do you guys think? i sorta need to know soon because i plan on buying the stuff in a coupel of days. thanks
Posted By: killer sonata
Date Posted: May 23, 2006 at 9:51 PM
Ofcourse the audio store is going to say that. They will say anything to get you to spend more money. They will tell you that your speakers will give you a BJ if you spend n extra $300 to get the better ones. lol. If I were you I would get the idea of the cap out of your head and stick with the alternator idea.
Posted By: stevdart
Date Posted: May 23, 2006 at 10:25 PM
You can't possibly burn anything up unless you employ an improper method of installation. That is, if you use a tiny little power wire with no protective fuse and try to pull too many amps (amplifier needs) through it. In that scenario, the wire would get hot enough to burn. But the amplifiers can only pull as much amperage as the alternator and battery will supply. Nothing will burn up if the alt can't supply as much as the amplifiers pull. Instead, the amps will get less than they want from the alternator and will pull power, in addition, from any car source that has power available (battery). The battery will be tapped, even if for the short duration that it is capable until it is dead, of supplying the extra demand that the alternator can't supply. While that happens, you will see the symptoms of a robbed power supply while driving the car...particularly at night when the headlights demand a load. Thus, the dilemna of the dimming headlights. Now, as I said, the amplifier will try to pull a given amount of amperage from the car's resources. If it doesn't get what it demands, will it fry? No. Instead, it will put out less power than expected. That's about all that will happen with the amplifier, but in the meantime the battery is being drained and the headlights can't get their share of power. See how it works? The cap is just that...a cap. Like when you say "Put a cap on it, it's done". Which means, a cap is of no value unless all else has been looked after first. Its value at this ultimate point is still questionable in that, theoretically, it may provide some cleansing to the power supply voltage. But you would have to be way up on noticing minute details in the sound to know if that cleansing effect is taking place. Bottom line, save your money for more crucial elements than a stiffening capacitor. If you ever get your system to the level where a cap can be of value, you won't be asking questions about it on a forum. You will be instructing on how to set up a first-class sound system. ------------- Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
Posted By: stormraider04
Date Posted: May 24, 2006 at 1:07 AM
ok good info stevdart. thanks alot guys. but one more thing. with the 1400 watts should i upgrade from my stock 115 amp alternator to a bigger one? and what brand alternator is good?
Posted By: xtremej
Date Posted: May 24, 2006 at 9:04 AM
Upgrade you alterantor, ohio is 1 brand you can look at there are quite a few brands out there now. Whichever one you choose make sure it comes with a warranty. Get a 160 amp at a bare minimum. Get a load test done on your current battery, its free at most parts stores. Replace battery if necessary. This will ensure that its up the task. I sell caps but I think I am the only one around here who tells the customer the truth in the fact they are mainly for looks not function.
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Posted By: stormraider04
Date Posted: May 24, 2006 at 12:25 PM
what will a load test do? what do i want the test to say?
Posted By: haemphyst
Date Posted: May 24, 2006 at 9:32 PM
nouseforaname wrote:
caps are crap, especially if you do compatitions. it takes them more time to discharge than your typical "burp" lasts plus creates resistance in your power wire, which may not be that big of a concern, but still something to consider.
huh? wha...?
That's the first time I've EVER heard either of those... What's your logic? I agree that caps are generally useless, but the other things are COMPLETELY new to me... ------------- It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."
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